Silicon carbide foam: extreme performance in a lightweight form

Paul Boughton

Silicon carbide (SiC) foam, available from Goodfellow, provides the exceptional hardness, high-temperature durability and performance of solid silicon carbide, but in an extremely lightweight and versatile foam structure. This combination of properties is highly valued in a range of industries, including aerospace, defence and semiconductor manufacturing.

The matrix of cells and ligaments of silicon carbide foam is completely repeatable, regular and uniform throughout the material, yielding a rigid, highly porous and permeable structure with a controlled density of metal per unit volume. Characteristics of SiC foam include:

* Exceptional hardness (Mohs 9) and performance – outstanding resistance to scratches, wear and corrosion;

* Structural stability at high temperatures – can operate up to 2200˚C;

* High thermal and electrical conductivity – unlike most other ceramics;

* Low thermal expansion – excellent thermal shock properties;

* High surface area-to-volume ratio – very lightweight;

* Low flow resistance – high filtration efficiency.

In applications, advantages derive from both the properties of SiC and the porosity/high surface area of the foam structure:

* High-temperature filters;

* Rocket nozzles;

* Heat shielding elements;

* Heat exchangers;

* Gas diffusers;

* Porous electrodes;

* Absorbers of electromagnetic radiation.

Silicon carbide foam is available in a standard pore size of 24 pores per centimetre (60 ppi), with a bulk density of 0.29, a porosity of 91 per cent and a thickness of 10mm. However, other porosities, densities and dimensions may be available upon request.

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